Abstract
Buthionine sulphoximine (BSO; 1mM) resulted in the depletion of glutathione (GSH) in HepG2 cells to 17+/-1.5% within 24h. This was not associated with apoptotic or necrotic cell death over this time period. Use of a human (Phase 1) cDNA custom toxicology-array and a larger scale (>10,000 gene) Affymetrix U95Av2 array identified a total of 48 and 104 genes, respectively, with a statistically significant (and >1.5-fold) change in expression. A total of 64 differentially expressed genes (6 of which were confirmed by real-time polymerase chain reaction) were suggestive of protein kinase C (PKC) activation. Activation of PKC-alpha (but not betaI or delta) was demonstrated at 24 h through activity measurements and through Western blot analysis of membrane-associated PKC-alpha protein. Activation did not occur in the presence of additional gamma-glutamylcysteine to prevent GSH depletion. Activation of PKC-alpha by GSH-depletion may, at least in part, be mediated by thiol oxidation and may contribute to a survival signal. If sustained, the activation may be important in non-genotoxic carcinogenesis.
Original language | English |
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Pages (from-to) | 168-80 |
Number of pages | 13 |
Journal | Toxicology |
Volume | 216 |
Issue number | 2-3 |
DOIs | |
Publication status | Published - 15 Dec 2005 |
Keywords
- Animals
- Apoptosis
- Oligonucleotide Array Sequence Analysis
- Protein Kinase C-alpha
- Carcinoma, Hepatocellular
- Enzyme Activation
- Glutathione
- Humans
- Buthionine Sulfoximine
- Cell Line, Tumor
- Reverse Transcriptase Polymerase Chain Reaction
- Protein Isoforms
- Cell Survival
- Liver Neoplasms
- L-Lactate Dehydrogenase
- Gene Expression Profiling
- Blotting, Western
- Gene Expression Regulation, Enzymologic
- Phosphorylation
- Protein Kinase C
- Time Factors
- Protein Transport